The assay of preparations containing pilocarpine and the characters of pilocarpine nitrate and hydrochloride / by H.D. Jowett.

  • Jowett, H. A. D. (Hooper Albert Dickinson)
Date:
[1899?]
Catalogue details

Licence: Public Domain Mark

Credit: The assay of preparations containing pilocarpine and the characters of pilocarpine nitrate and hydrochloride / by H.D. Jowett. Source: Wellcome Collection.

    7/12 (page 5)
    be able to determine the latter factor with greater accuracy, since this figure gives us absolutely no information as to the amount of pilocarpine present, whilst the method described does so within the limits of experimental error above indicated Characters gf Pilocarpine Nitrate and Hydrochloride. In order to be certain of the identity of pilocarpine nitrate from various sources, I prepared the salt from two varieties of aborandi leaves, viz., the true jaborandi and the small leaved variety, Maranham jaborandi, and I also purified some pilocarpine nitrate purchased from two manufacturers. I found that, contrary to the statements of Paul and Cownley, and Petit and Polonowsky, the nitrate is easily purified by repeated recrystallisation from strong alcohol, and this method was used to purify the salts. The proof of the identity of the pilocarpine nitrate prepared from th se different sources and of its chemical purity was fur¬ nished by the fact that the salt, after several recrystallisations from different solvents and when obtained in different fractions, under¬ went no change in the melting point or specific rotatory power, and that the physical constants of the purified salt from every source were identical. The physical constants of the pure salt were :— Jowett. Petit and Polonowsky. Melting Point. 178’ . 177 - 178’ [a]D + 82-9° . + 82-2° Solubility in water. .1 in 6’4 (at 20’). 1 in 7 (at 18°). A further proof of the identity of pilocarpine nitrate as obtained from different sources is furnished by the agreement of the factors obtained by me and those given by Petit and Polonowsky. I am unable to understand why a sample of pilocarpine nitrate, melting point 141-7°, when recrystallised from alcohol in different fractions should give no alteration in the melting point, as I obtained the following results with a commercial specimen melting at 168 , and I have never met with a preparation with a lower melting point than 167°. Melting points of pilocarpine nitrate after recrystallisation from alcohol:— Melting point of original salt After first recrystallisation ,, second ,, ,, third ,, „ fourth „ 168 175 176 176 178 and [a]u = + 82*94